Andy McMillin returned to his “backyard” Saturday to win the overall title in the inaugural SCORE Imperial Valley 250 off-road race.

Subbing for Rob MacCachren, McMillin overcame a sand storm created by gale-force winds to complete the 249-mile course in 4 hours, 31 minutes and 1 second at an average speed of 55.19 mph.

Steve Sourapas was second both overall and in the featured TrophyTruck class in 4:37:16, giving San Diego County drivers a sweep of the top two positions in the first Imperial Valley race in the 41-year history of the SCORE desert series.

Only 53 of the 131 starters finished the race.

“This race was a fantastic success,” said SCORE President Roger Norman.

“Despite the dust storm, and we had white-out conditions at times, we attracted more spectators than we anticipated, maybe close to 30,000.

“We will absolutely return to the Imperial Valley.”

McMillin, who teamed with MacCachren to finish second in last year’s SCORE Baja 1000, took over the cockpit for the Imperial Valley 250 because MacCachren was committed to a short-course race this weekend.

“I grew up in this desert,” said McMillin. “I felt really relaxed and comfortable knowing the terrain and the feel of the desert around Superstition Mountain.”

McMillin is the son of Scott McMillin and the grandson of off-road racing legend Corky McMillin. His family, including his sister Jessica, uncle Mark and cousins Dan and Luke have all won SCORE races in addition to off-roading for decades over the area of Saturday’s race.

“It was a lot of fun out there today and I was pumped to get on top of the podium,” said Andy McMillin.

“It means a lot to win this race in my own backyard. Being familiar with the terrain and the course really helped. It was a really fun course. It was really fast and it had some silt and really deep holes.”

Not to mention sand.

The strong winds that whipped San Diego County Friday night and Saturday reached the Imperial Valley 250 course area — an 83-mile loop between Plaster City and Superstition Mountain to the north — around the time the Trophy Trucks were starting at 1 p.m. Saturday.

“The visibility was terrible for a lot of the race, but Rob’s truck ran flawlessly,” said McMillin, whose five previous SCORE wins included an overall title in a Baja 1000. “They had a really good setup for this race.”

The overall and Open motorcycle winner was the team of Ian Young (San Clemente) and Mark Samuels (Yucaipa). They covered the three-loop course in 5:14:55 on a Honda.

Fallbrook’s Mike Cafro teamed with Mexico’s Javier Robles; Jorie Williams of Longview, Wash., and Robbie Mitchell of Price, Utah, to win the overall ATV title in 6:09:01 on a Honda.

Other class winners from San Diego County were San Diego’s Noah Ostanik (open pickup trucks) and Julian’s Giovanni Spinali (motorcycle riders 40 and older).